Creatine is a naturally occurring amino acid derived from the amino acids glycine, arginine, and methionine. Although it is found in meat and fish, it is also synthesized by humans. Creatine is predominantly used as a fuel source in muscle. About 65% of creatine is stored in the musculature of mammals as phosphocreatine (creatine bound to a phosphate molecule).
Muscular contractions are fueled by the dephosphorylation of adenosine triphosphate (ATP) to produce adenosine diphosphate (ADP). In the absence of a mechanism to replenish ATP stores, the supply of ATP would be totally consumed in 1-2 seconds. Phosphocreatine serves as a major source of phosphate from which ADP is regenerated to ATP. Within six seconds following the commencement of exercise, muscular concentrations of phosphocreatine drop by almost 50%. Creatine supplementation has been shown to increase the concentration of creatine in the muscle (Harris R C, Soderlund K, Hultman E. Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clin Sci (Lond). 1992 September; 83(3):367-74) and further, the supplementation enables an increase in the resynthesis of phosphocreatine (Greenhaff P L, Bodin K, Soderlund K, Hultman E. Effect of oral creatine supplementation on skeletal muscle phosphocreatine resynthesis. Am J. Physiol. 1994 May; 266(5 Pt 1):E725-30) leading to a rapid replenishment of ATP within the first two minutes following the commencement of exercise. Through this mechanism, creatine is able to improve strength and reduce fatigue (Greenhaff P L, Casey A, Short A H, Harris R, Soderlund K, Hultman E. Influence of oral creatine supplementation of muscle torque during repeated bouts of maximal voluntary exercise in man. Clin Sci (Lond). 1993 May; 84(5):565-71).
The beneficial effects of creatine supplementation with regard to skeletal muscle are apparently not restricted to the role of creatine in energy metabolism. It has been shown that creatine supplementation in combination with strength training results in specific, measurable physiological changes in skeletal muscle compared to strength training alone. For example, creatine supplementation amplifies the strength training-induced increase of human skeletal satellite cells as well as the number of myonuclei in human skeletal muscle fibres (Olsen S, Aagaard P, Kadi F, Tufekovic G, Verney J, Olesen J L, Suetta C, Kjaer M. Creatine supplementation augments the increase in satellite cell and myonuclei number in human skeletal muscle induced by strength training. J. Physiol. 2006 June 1; 573(Pt 2):525-34). Satellite cells are the stem cells of adult muscle. They are normally maintained in a quiescent state and become activated to fulfill roles of routine maintenance, repair and hypertrophy (Zammit P S, Partridge T A, Yablonka-Reuveni Z. The Skeletal Muscle Satellite Cell: The Stem Cell That Came In From the Cold. J Histochem Cytochem. 2006 Aug. 9). ‘True’ muscle hypertrophy can be defined as “as an increase in fiber diameter without an apparent increase in the number of muscle fibers, accompanied by enhanced protein synthesis and augmented contractile force” (Sartorelli V, Fulco M. Molecular and cellular determinants of skeletal muscle atrophy and hypertrophy. Sci STKE. 2004 July. 27; 2004(244):re11). Postnatal muscle growth involves both myofiber hypertrophy and increased numbers of myonuclei—the source of which are satellite cells (Olsen S, Aagaard P, Kadi F, Tufekovic G, Verney J, Olesen J L, Suetta C, Kjaer M. Creatine supplementation augments the increase in satellite cell and myonuclei number in human skeletal muscle induced by strength training. J. Physiol. 2006 June 1; 573(Pt 2):525-34).
Although creatine is used predominantly in muscle cells and most of the total creatine pool is found in muscle, creatine is actually synthesized in the liver and pancreas. Thus, the musculature's creatine concentration is maintained by the uptake of creatine from the blood stream regardless of whether the source of creatine is endogenous, i.e. synthesized by the liver or pancreas, or dietary, i.e. natural food sources or supplemental sources. The creatine content of an average 70 kg male is approximately 120 g with about 2 g being excreted as creatinine per day (Williams M H, Branch J D. Creatine supplementation and exercise performance: an update. J Am Coll Nutr. 1998 June; 17(3):216-34). A typical omnivorous diet supplies approximately 1 g of creatine daily, while diets higher in meat and fish will supply more creatine. As a point of reference, a 500 g uncooked steak contains about 2 g of creatine which equates to more than two 8 oz. steaks per day. Since most studies examining creatine supplementation employ dosages ranging from 2-20 g per day it is unrealistic to significantly increase muscle creatine stores through merely food sources alone. Therefore, supplemental sources of creatine are an integral component of increasing, and subsequently maintaining supraphysiological, muscular creatine levels.
Creatine supplementation, thus results in positive physiological effects on skeletal muscle, such as: performance improvements during brief high-intensity anaerobic exercise, increased strength and enhanced muscle growth.
Creatine monohydrate is a commonly used supplement. Creatine monohydrate is soluble in water at a rate of 75 ml of water per gram of creatine. Ingestion of creatine monohydrate, therefore, requires large amounts of water to be co-ingested. Additionally, in aqueous solutions creatine is known to convert to creatinine via an irreversible, pH-dependent, non-enzymatic reaction. Aqueous and alkaline solutions contain an equilibrium mixture of creatine and creatinine. In acidic solutions, on the other hand, the formation of creatinine is complete. Creatinine is devoid of the ergogenic beneficial effects of creatine. It is therefore desirable to provide, for use in individuals, e.g. animals and humans, forms and derivatives of creatine with improved characteristics such as stability and solubility. Furthermore, it would be advantageous to do so in a manner that provides additional functionality as compared to creatine monohydrate alone.
The manufacture of hydrosoluble creatine salts with various organic acids have been described. U.S. Pat. No. 5,886,040, purports to describe a creatine pyruvate salt with enhanced palatability which is resistant to acid hydrolysis.
U.S. Pat. No. 5,973,199, purports to describe hydrosoluble organic salts of creatine as single combination of one mole of creatine monohydrate with one mole of the following organic acids: citrate, malate, fumarate and tartarate individually. The resultant salts described therein are claimed to be from 3 to 15 times more soluble, in aqueous solution, than creatine itself.
U.S. Pat. No. 6,166,249, purports to describe a creatine pyruvic acid salt that is highly stable and soluble. It is further purported that the pyruvate included in the salt may be useful to treat obesity, prevent the formation of free radicals and enhance long-term performance.
U.S. Pat. No. 6,211,407 purports to describe dicreatine and tricreatine citrates and a method of making the same. These dicreatine and tricreatine salts are claimed to be stable in acidic solutions, thus hampering the undesirable conversion of creatine to creatinine.
U.S. Pat. No. 6,838,562, purports to describe a process for the synthesis of mono, di, or tricreatine orotic acid, thioorotic acid, and dihydroorotic acid salts which are claimed to have increased oral absorption and bioavailability due to an inherent stability in aqueous solution. It is further claimed that the heterocyclic acid portion of the salt acts synergistically with creatine.
U.S. Pat. No. 7,109,373, incorporated herein in its entirety by reference, purports to describe creatine salts of dicarboxylic acids with enhanced aqueous solubility.
The above disclosed patents recite creatine salts, methods of synthesis of the salts, and uses thereof. However, nothing in any of the disclosed patents teaches, suggests or discloses a compound comprising a creatine molecule bound to a fatty acid.
In addition to salts, creatine esters have also been described. U.S. Pat. No. 6,897,334 describes method for producing creatine esters with lower alcohols i.e. one to four carbon atoms, using acid catalysts. It is stated that creatine esters are more soluble than creatine. It is further stated that the protection of the carboxylic acid moiety of the creatine molecule by ester-formation stabilizes the compound by preventing its conversion to creatinine. The creatine esters are said to be converted into creatine by esterases i.e. enzymes that cleave ester bonds, found in a variety of cells and biological fluids.
Fatty acids are carboxylic acids, often containing a long, unbranched chain of carbon atoms and are either saturated or unsaturated. Saturated fatty acids do not contain double bonds or other functional groups, but contain the maximum number of hydrogen atoms, with the exception of the carboxylic acid group. In contrast, unsaturated fatty acids contain one or more double bonds between adjacent carbon atoms, of the chains, in cis or trans configuration
The human body can produce all but two of the fatty acids it requires, thus, essential fatty acids are fatty acids that must be obtained from food sources due to an inability of the body to synthesize them, yet are required for normal biological function. The essential fatty acids being linoleic acid and α-linolenic acid.
Examples of saturated fatty acids include, but are not limited to myristic or tetradecanoic acid, palmitic or hexadecanoic acid, stearic or octadecanoic acid, arachidic or eicosanoic acid, behenic or docosanoic acid, butyric or butanoic acid, caproic or hexanoic acid, caprylic or octanoic acid, capric or decanoic acid, and lauric or dodecanoic acid, wherein the aforementioned comprise from at least 4 carbons to 22 carbons in the chain.
Examples of unsaturated fatty acids include, but are not limited to oleic acid, linoleic acid, linolenic acid, arachidonic acid, palmitoleic acid, eicosapentaenoic acid, docosahexaenoic acid and erucic acid, wherein the aforementioned comprise from at least 4 carbons to 22 carbons in the chain.
Fatty acids are capable of undergoing chemical reactions common to carboxylic acids. Of particular relevance to the present invention are the formation of salts and the formation of esters. The majority of the above referenced patents are creatine salts. These salts, esterification via carboxylate reactivity, may essentially be formed, as disclosed in U.S. Pat. No. 7,109,373, through a relatively simple reaction by mixing a molar excess of creatine or derivative thereof with an aqueous dicarboxylic acid and heating from room temperature to about 50° C.
Alternatively, a creatine-fatty acid may be synthesized through ester formation. The formation of creatine esters has been described (Dox A W, Yoder L. Esterification of Creatine. J. Biol. Chem. 1922, 67, 671-673). These are typically formed by reacting creatine with an alcohol in the presence of an acid catalyst at temperatures from 35° C. to 50° C. as disclosed in U.S. Pat. No. 6,897,334.
While the above referenced creatine compounds have attempted to address issues such as stability and solubility in addition to, and in some cases, to add increased functionality as compared to creatine alone, no description has yet been made of any creatine-fatty acid compound, particularly that comprising a saturated fatty acid.